Cylinder stroke position measurement device

Abstract

A cylinder stroke position measurement device for enabling common use of a rotation sensor unit in measurement of a cylinder stroke position by detecting an amount of rotation of a rotary roller by means of a rotation sensor. A cylinder is provided at its head portion with a base member 300 having an opening accommodating at least a rotary roller and a rotation sensor section. A pressing member, the rotary roller, and the rotation sensor section are held on one side of a sensor holding member, while a coupling member for example is provided on the opposite side of the sensor holding member, thus constituting a rotation sensor unit. The sensor holding member is attached to the base member such that the rotary roller and the rotation sensor section are accommodated in the opening of the base member 300 . The rotary roller is pressed by the pressing member against the surface of a rod. The rotation sensor section detects an amount of rotation of the rotary roller. The coupling member electrically couples the rotation sensor section with an external signal line.

1. A cylinder stroke position measurement device for measuring a stroke position of a cylinder, comprising:
 a rotary roller being in contact with a surface of a rod of the cylinder and rotating in accordance with displacement of the rod; 
 a pressing member pressing the rotary roller against the surface of the rod; 
 a rotation sensor section detecting an amount of rotation of the rotary roller; 
 a coupling member electrically coupling the rotation sensor section with an external signal line; 
 a base member attached to a head portion of the cylinder and having an opening accommodating at least the rotary roller and the rotation sensor section; 
 a sensor holding member holding the pressing member, the rotary roller, and the rotation sensor section on its one side, and attached to the base member such that the rotary roller and the rotation sensor section are accommodated in the opening of the base member; 
 
     the coupling member being arranged on an opposite side of the sensor holding member; and
 a lid member attached to the sensor holding member so as to cover the coupling member. 
 
   
   
     2. The cylinder stroke position measurement device as claimed in  claim 1 , wherein the pressing member is a leaf spring, and the leaf spring is accommodated in a recess formed in the sensor holding member such that the rotary roller is pressed against the surface of the rod in accordance with deflection of the leaf spring. 
   
   
     3. The cylinder stroke position measurement device as claimed in  claim 1 , wherein the pressing member is a coil spring, and the coil spring is accommodated in a recess formed in the sensor holding member such that the rotary roller is pressed against the surface of the rod in accordance with deflection of the coil spring. 
   
   
     4. A cylinder stroke position measurement device for measuring a stroke position of a cylinder, comprising:
 a rotary roller being in contact with a surface of a rod of the cylinder and rotating in accordance with displacement of the rod; 
 a pressing member pressing the rotary roller against the surface of the rod; 
 a rotation sensor section detecting an amount of rotation of the rotary roller; 
 a coupling member electrically coupling the rotation sensor section with an external signal line; 
 a base member attached to a head portion of the cylinder and having an opening accommodating at least the rotary roller and the rotation sensor section; and 
 a sensor holding member holding the pressing member, the rotary roller, and the rotation sensor section on its one side, and attached to the base member such that the rotary roller and the rotation sensor section are accommodated in the opening of the base member, wherein 
 the base member is provided with dust seals at different positions in a stroke direction of the rod such that the rotary roller is located between the dust seals. 
 
   
   
     5. The cylinder stroke position measurement device as claimed in  claim 4 , wherein the pressing member is a leaf spring, and the leaf spring is accommodated in a recess formed in the sensor holding member such that the rotary roller is pressed against the surface of the rod in accordance with deflection of the leaf spring. 
   
   
     6. The cylinder stroke position measurement device as claimed in  claim 4 , wherein the pressing member is a coil spring, and the coil spring is accommodated in a recess formed in the sensor holding member such that the rotary roller is pressed against the surface of the rod in accordance with deflection of the coil spring. 
   
   
     7. A cylinder stroke position measurement device for measuring a stroke position of a cylinder, comprising:
 a rotary roller being in contact with a surface of a rod of the cylinder and rotating in accordance with displacement of the rod; 
 a pressing member pressing the rotary roller against the surface of the rod; 
 a rotation sensor section detecting an amount of rotation of the rotary roller; 
 a coupling member electrically coupling the rotation sensor section with an external signal line; 
 a base member attached to a head portion of the cylinder and having an opening accommodating at least the rotary roller and the rotation sensor section; 
 a sensor holding member holding the pressing member, the rotary roller, and the rotation sensor section on its one side, and attached to the base member such that the rotary roller and the rotation sensor section are accommodated in the opening of the base member; and 
 a lever member is provided for rotatably supporting the rotary roller, wherein 
 the opening of the base member is formed with an oblique hole extending from an extension side of the rod to a retraction side of the rod, along a direction from the outer periphery to the inner periphery of the base member; and 
 the lever member is provided with an oblique part corresponding to the oblique hole, the oblique part of the lever member being inserted into the oblique hole. 
 
   
   
     8. The cylinder stroke position measurement device as claimed in  claim 7 , wherein the pressing member is a leaf spring, and the leaf spring is accommodated in a recess formed in the sensor holding member such that the rotary roller is pressed against the surface of the rod in accordance with deflection of the leaf spring. 
   
   
     9. The cylinder stroke position measurement device as claimed in  claim 7 , wherein the pressing member is a coil spring, and the coil spring is accommodated in a recess formed in the sensor holding member such that the rotary roller is pressed against the surface of the rod in accordance with deflection of the coil spring.